Slip ring apparatus for signal transfer



June 25, 1963 J. s. ADKINS 3,095,252

SLIP RING APPARATUS FOR SIGNAL TRANSFER Filed July 25, 1960 22 r33 CONTR/OLLED g gg g f .1 STATION *2 r-- E 2 15 15 1a 16 ,1 I! 1z 19 n 11 p I 1/ j 12 E J I 1x /2/// L{! 1 .19 7 16 2/ -To CONTROLLED STATiON I CONTROL STATION W? INVENTOR. dmv 6. flak/Mi United States Patent 3,095,252 SLIP RING APPARATUS FOR SIGNAL TRANSFER John S. Adkins, 2555 La Mesa Drive, Santa Monica, Calif. Filed July 25, 1960, Ser. No. 44,952 3 Claims. (Cl. 3395) This invention relates to rotary signal apparatus, and more particularly to a unique brush and slip ring assembly for transferring a multiplicity of separate signals simultaneously through separate connections between relatively movable parts.

In a variety of situations, it is necessary to couple parts of an electrical system that are supported on relatively movable coaxial structures. For example, a system may include a control center on one structure, and apparatus on the other structures to receive a plurality of signals from the control center.

It will be apparent that numerous wires or leads are needed for such equipment. As will also be apparent, it is highly desirable for many purposes that the size and complexity of means for transferring signals from the control center leads to the controlled apparatus leads should be kept to a minimum.

As heretofore known, no satisfactory signal transfer mechanism has been devised for coaxial structures wherein respective ones of a number of leads from apparatus on one structure are to be connected to leads of respective apparatus on different structures. Such transfer mechanisms as have been employed have various undesired characteristics, in that they require too many moving parts, wire connections are unduly complex, and they are not capable of being combined so as to provide a desired small, compact mechanism.

It is another object of my invention to provide a unique signal transfer apparatus in which a single element carries sets of compact elements for each of a number of devices coaxial therewith.

A further object of my invention is to provide rotary signal apparatus that is characterized by great ease of assembly and disassembly.

A still further object of my invention is to provide signal transfer apparatus for devices that are relatively movable about a common axis, which employs a minimum number of component parts of simple design and rugged construction.

The above and other objects and advantages of my invention will become apparent from the following description taken in conjunction with the accompanying drawing of illustrative embodiments thereof, in which:

FIGURE 1 is a longitudinal sectional view of a rotary signal transfer device in accordance with my invention, showing different sets of slip rings held on a common shaft of insulating material, with leads to each of the slip rings of both sets being led to the rings by one end of the shaft, and showing separate brush assemblies having housings separately and rotatably mounted on the shaft, with respective leads in contact with each of the slip rings being embedded in the associated brush housing;

FlGURE 2 is a fragmentary sectional view taken along the line 22 of FIGURE 1, to illustrate a suitable brush arrangement; and

FIGURE 3 is a longitudinal sectional view of signal transfer apparatus of my invention employing multiple sets of slip rings and brush assemblies for a plurality of different structures that are rotatable about a common axis.

Referring to FIGURE 1, there is shown a shaft that supports spaced sets 11, 12 of slip rings of conductive metal. Surrounding the shaft 10 are spaced sleeves,

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shown byway of example as cylinders 13, 14 which carry respective sets of wire contacts or brushes 15, 16 for engaging the rings 11, 12. As shown, the cylinders 13, 14 are mounted for rotation relative to the shaft 10' by means of respective pairs of ball bearings 17, 18.

As in the embodiment shown, the cylinders 13, 14 surround portions of the shaft 10 that may be of different diameters, so that the inner races of one of the bearings of the pairs 17, 18 are in abutment with the radial transitions between the different diameters. Snap rings 19 are employed to engage the inner races of the remaining bearings of the pairs 17, 18. The sleeves 13, 14 are captured between the outer races of the bearings, and for this purpose the ends of the cylinders 13, 14 are suitably grooved.

The brushes 15, 16 are extensions of lead wires 15', 16' that are embedded in the bodies of the cylinders 13, 14. The slip ring assembly is also provided with leads 11', 12' that are embedded in the shaft 10. The leads 11, 12' are led through the rings 11, 12 to one end of the shaft 10, and through a disk 20 that is molded to the shaft at that end. With this arrangement, the leads 11, 12' extending from the one end of the shaft 10, and the leads 15', 16 extending from respective ends of the cylinders 13, 14 are arranged for connection to respective sets of electrical apparatus.

The leads 11', 12' are connected to apparatus 21 that functions to control apparatus 22, 23 contained on structures that rotate, relative to each other and to the control apparatus 21, about the axis of the shaft 10. The control apparatus 21 and the controlled apparatus 22, 23 may, for example, include coaxially arranged and independently rotatable multi-position switch stations, wherein the central or control station supplies signals to slip rings selectively, and the associated brush connections present the signals at corresponding terminals about the respective switch stations. In such an arrangement, circuits may be connected to switch terminals so as to operate in accordance with the angular position of the associated switch station and the manner in which signals are programmed to the slip rings. The arrangement is also one of greatest simplicity of arrangement of the parts and the lead wires, and is well adapted for a compact structure to occupy a minimum of space.

' In fabricating .a structure of the type above described, the respective leads 11', 12 are connected, as by soldering, to the rings 11, 12. Each of the leads 11, 12' is then led through the centers of the rings 11, 12 to one end. The rings 11, 12 are located in a mold having the desired cylindrical shape, and plastic material is injected into the mold to fill all spaces in the cavity not occupied by the rings 11, 12 and the leads 11, 12'. The plastic shaft is then cured, and subsequently grooved at the desired locations to receive the snap ring 19. The disk 20 is prepared with the appropriate number of openings and the leads 11', 12 are threaded through the disk 20, which is then molded onto the end of the shaft 10.

The cylinders 13, 14 are formed in a similar manner. The brushes 15, 16 are arranged with the leads 15', 16 extending in an axial direction. Thus arranged in a suitable mold, plastic material is injected into the mold, and subsequently cured to provide the cylinders 13, 14. After grooving the cylinders 13, 14, so as to provide radial shoulders to be located between the confronting edges of the outer races of the bearings 17', 18, the cylinders 13, 14 are located on the respective sets of bearings 17, 18, and the snap rings 19 are located in the grooves formed therefor.

In locating the cylinders 13, 14 on the shaft 10, care is exercised to insure that the brushes 15, 16 are in firm biased engagement with the slip rings 11, 12. To this end, the brushes 15, 16 may be formed of spring metal, with the ends thereof normally spaced from the center of the cylinder a distance less than the radius of the shaft (see FIGURE 2). When the cylinders are located on the shaft, the brushes are forced out of the way. Thereafter, the brushes are self-biased against the rings.

In the embodiment of my invention shown in FIG- URE 3, a shaft 30 is provided with three sets of slip rings 31, 32, 33, all of which have leads that extend through one end of the shaft 30, and through a disk 34 that is bonded to the shaft. The portions of the leads extending through the disk 34 are indicated at 35 in FIG- URE 3.

Spaced along the shaft 30, and mounted for rotation thereon in the manner of the cylinders 13, 14 of FIG- URE l, are spaced cylinders 36, 37, 38. The cylinders 36-38 support respective sets of brushes 39-41, and have leads 39-41 embedded therein and extending therefrom, e.g., from one end thereof.

The cylinders 36-38 are mounted in sleeve elements 4244 for unitary rotation therewith, e.g., by frictional engagement. Mounted on the lateral surfaces of the sleeves 42-44 are respective pairs of bearings 45-47, and supported on the outer races of the bearings 45-47 are respective sleeve structures 50, 51, 52 which it is desired shall be able to undergo angular movement relative to each other.

The disk 34 is adapted to be secured, as at 60, to a frame structure 61. As shown in FIGURE 2, the frame 61 is also secured, as at 62, to the sleeve 52. The sleeve 51 is provided with an end ring 64 having an inner diameter substantially the same as that of the sleeve 44, the sleeve 44 being secured as at 65 to the ring 64. Simi larly, the sleeve 43 is secured at 67 to an integral ring 68 on the sleeve 50. The sleeve 42 is secured at 69 to a disk 70.

With the above-described structural arrangement, it will be seen that the sleeves 42, 43, 44 may be attached to structures movable on a common axis by the rings 64, 63 and the disk 70. Signal controlled apparatus on a structure to which the disk 70 is attached receives signals through the leads 35 that are connected to the slip rings 31, and through the brushes 39 and brush leads 39'. As will be apparent, the brush assembly is fixed relative to a structure to which the disk 70 is secured.

In similar fashion, electrical apparatus on a structure to which the ring element 68 is secured is provided with signals through the slip rings 32, the brushes 40 and the brush leads 40. Signals are supplied through the slip rings 33, the brushes 41 and the leads 41' to electrical apparatus on a structure to which the ring element 64 is fixed.

As will be apparent, the signal transfer system structure of FIGURE 3 is extremely compact, with the number of wires being kept to a minimum and arranged in the simplest manner to accomplish the desired result.

Although I have illustrated and described particular embodiments of my invention, it will be apparent that various modifications can be made therein without departing from the spirit and scope of my invention. Accordingly, I do not intend that my invention be limited except by the appended claims.

I claim:

1. Signal transfer apparatus comprising: spaced sets of coaxial slip rings, the slip rings in each set being spaced; a respective lead connected at one end to each slip ring, said leads extending from their slip rings toward one end of the assembly; a shaft including nonconductive material supporting said slip rings and embedding said leads therein; spaced sleeves including nonconductive material, said sleeves surrounding said shaft, each sleeve surrounding a set of slip rings; means supporting said sleeves and said shaft for relative angular movement; brush elements supported by said sleeves and engaging said slip rings; and leads extending through said sleeves to the brush elements.

2. The combination defined in claim 1, further including means to aid in securing each sleeve to a structure; and a disk element secured to said one end of the shaft, said leads from said slip rings extending through said disk element.

3. Apparatus for transferring signals from a control station to each of a number of controlled stations, wherein such stations are on structures that are subject to independent relative movement about a common axis, comprising: a shaft including nonconductive material on the axis to be secured at one end to the structure supporting the control station; a plurality of spaced slip ring elements supported in spaced sets on said shaft; respective leads extending from the slip ring elements and through said shaft to said one end of the shaft for connection to the control station; spaced sleeves including non-conductive material surrounding said shaft, each sleeve surrounding a set of slip rings; means supporting said sleeves and said shaft for relative angular movement; spaced brush elements supported by said sleeves extending generally transversely therethrough, said brush elements being arranged so as to be maintained in engagement with respective slip ring elements; and leads extending through said sleeves to the brush elements, the brush leads from each sleeve being adapted for connection to a respective controlled station.

References Cited in the file of this patent UNITED STATES PATENTS 561,699 Cooley June 9, 1896 2,473,526 Hood et a1. June 21, 1949 FOREIGN PATENTS 881,583 France Jan. 28, 1943 

1. SIGNAL TRANSFER APPARATUS COMPRISING: SPACED SETS OF COAXIAL SLIP RINGS, THE SLIP RINGS IN EACH SET BEING SPACED; A RESPECTIVE LEAD CONNECTED AT ONE END TO EACH SLIP RING, SAID LEADS EXTENDING FROM THEIR SLIP RINGS TOWARD ONE END OF THE ASSEMBLY; A SHAFT INCLUDING NONCONDUCTIVE MATERIAL SUPPORTING SAID SLIP RINGS AND EMBEDDING SAID LEADS THEREIN; SPACED SLEEVES INCLUDING NONCONDUCTIVE MATERIAL, SAID SLEEVES SURROUNDING SAID SHAFT, EACH SLEEVE SURROUNDING A SET OF SLIP RINGS; MEANS SUPPORTING SAID SLEEVES AND SAID SHAFT FOR RELATIVE ANGULAR MOVEMENT; BRUSH ELEMENTS SUPPORTED BY SAID SLEEVES AND ENGAGING SAID SLIP RINGS; AND LEADS EXTENDING THROUGH SAID SLEEVES TO THE BRUSH ELEMENTS. 